early bird special

[eickm]

I have been trying to find the cause of backfiring on deceleration, and have checked the usual items (valves adjusted, exhaust tight, air cleaner clean, idle screw adjustment) with no luck. In browsing the owners manual, I found that I was supposed to periodically clean the muffler by removing three drain plugs and banging on the muffler while it was running. OK, so in removing the plugs two of the three bold heads broke off and now I will have to drill them out, etc. But, I am wondering if this is a dead-end anyway, and if this maintenance is really important and/or could cause backfiring. Any thoughts? Mike

[Eric L. Green]

On Fri, 15 Oct 2004, eickm wrote:

> In browsing the owners manual, I found that I was supposed to > periodically clean the muffler by removing three drain plugs and > banging on the muffler while it was running. OK, so in removing the > plugs two of the three bold heads broke off and now I will have to > drill them out, etc. > > But, I am wondering if this is a dead-end anyway, and if this > maintenance is really important and/or could cause backfiring. Any > thoughts?

My KLR has 20,000 miles on it. As far as I can tell, this service had never been done on my KLR. So I lubed the bolts up good with penetrating oil, tapped on them with a ball peen, let them soak for a couople of hours in penetrating oil, etc. prior to attempting to unscrew them ('cause I know what happens to bolts in an exhaust system!), unscrewed them, started my bike, started thumping the muffler with my rubber mallet while revving the engine, and .... NOTHING. Nada. Not one piece of soot. Not one little particle of black carbon. Indeed, the only smoke was what little penetrating oil had not already evaporated by that time (a couple hours after originally applying it) hitting the road. My provisional conclusion is that this is just some nonsense put there in the manual to satisfy the Forest Service that there's nothing in the muffler that could fly out the back and cause a spark (i.e., part of the USFS muffler certification requirements), rather than something real. -E

[Bogdan Swider]

> > > In browsing the owners manual, I found that I was supposed to > periodically clean the muffler by removing three drain plugs and > banging on the muffler while it was running. OK, so in removing the > plugs two of the three bold heads broke off and now I will have to > drill them out, etc. > > But, I am wondering if this is a dead-end anyway, and if this > maintenance is really important and/or could cause backfiring. Any > thoughts? > > Mike

When new to the klr I asked some experienced klristas about the muffler cleaning which I - obediently to the manual - did on occasion. I was told that nobody bothered with this. I haven't done it since with no ill effects. Wonder if anyone says anything different now. I don't remember the topic mentioned on the list. As to the backfiring, the consensus is that it's caused by a lean condition. I believe that when the stock muffler burns out its glass packing - early in its life - it leans our the mixture somewhat. Did you say that you turned out the pilot screw somewhat ? You wrote idle mixture. You may want to lift the needle with a small washer or two. Bogdan

[klr650]

eickm wrote:

> In browsing the owners manual, I found that I was supposed to > periodically clean the muffler by removing three drain plugs and > banging on the muffler while it was running. OK, so in removing the > plugs two of the three bold heads broke off and now I will have to

I've done this once or twice with nothing more than a poof of dust coming out. Have you pulled your plug to look at it? Jim

[eickm]

--- In DSN_klr650@yahoogroups.com, KLR650 wrote:

> eickm wrote: > > In browsing the owners manual, I found that I was supposed to > > periodically clean the muffler by removing three drain plugs and > > banging on the muffler while it was running. OK, so in removing

the

> > plugs two of the three bold heads broke off and now I will have

to

> > I've done this once or twice with nothing more than a poof of dust > coming out. Have you pulled your plug to look at it? > > Jim

No, I haven't pulled the spark plug but will put that next on the list of things to try ... don't know why I have not done this yet! Mike

[denis@teachlinux.com]

Mike, I tried to do the same thing a few months ago and broke them off also. Everyone on the list said to not bother fixing the bolts, since it never made much difference. Denis A14

On Fri, 15 Oct 2004, eickm wrote: > > > > I have been trying to find the cause of backfiring on deceleration, > and have checked the usual items (valves adjusted, exhaust tight, air > cleaner clean, idle screw adjustment) with no luck. > > In browsing the owners manual, I found that I was supposed to > periodically clean the muffler by removing three drain plugs and > banging on the muffler while it was running. OK, so in removing the > plugs two of the three bold heads broke off and now I will have to > drill them out, etc. > > But, I am wondering if this is a dead-end anyway, and if this > maintenance is really important and/or could cause backfiring. Any > thoughts? > > Mike > > > > > > > List sponsored by Dual Sport News at www.dualsportnews.com. List FAQ courtesy of Chris Krok at: www.bigcee.com/klr650faq.html > Unsubscribe by sending a blank message to: > DSN_klr650-unsubscribe@yahoogroups.com . > > > Yahoo! Groups Links > > > > > > > >

[eickm]

--- In DSN_klr650@yahoogroups.com, Bogdan Swider wrote: ... snip ... > mentioned on the list. As to the backfiring, the consensus is that it's > caused by a lean condition. I believe that when the stock muffler burns out > its glass packing - early in its life - it leans our the mixture somewhat. > Did you say that you turned out the pilot screw somewhat ? You wrote idle > mixture. You may want to lift the needle with a small washer or two. > > Bogdan Yes, I had installed an externally adjustable pilot screw about a year ago with good results. I did turn it out with no effect on the backfire.

[Bogdan Swider]

> > Yes, I had installed an externally adjustable pilot screw about a > year ago with good results. I did turn it out with no effect on the > backfire.

Also have you checked the exhaust system from the head on down for leaks ? Bogdan

[Alan L Henderson]

eickm wrote:

> > > But, I am wondering if this is a dead-end anyway, and if this > maintenance is really important and/or could cause backfiring. Any > thoughts? > > Mike > >

I agree with everyone else that it is worthless to check as nothing ever comes out. May be a left over from the two stroke era where there actually was carbon generated. Sounds like a lean condition. Check to make sure the deceleration enriching circuit in the carb is functioning. Any thing that increases the ease of gas flow in and out of the engine can cause a lean condition. High flow air filters and high flow exhausts have to be compensated for as do modifications to the still air box. You need to check all of the connections in the intake tract to make sure that none are leaking air. You also have to check the exhaust system to make sure there are no leaks before the end of the muffler. Check the connection between the engine and the exhaust header pipe as that has caused problems for some in the past. Check the connection between the head pipe and the muffler itself. That's all I can think of at the moment but it gives you some things to check. Alan Henderson A13 Iowa

[eickm]

Thanks to all for the good tips; I have a better feeling of how to proceed now! Mike --- In DSN_klr650@yahoogroups.com, Alan L Henderson wrote:

> eickm wrote: > > > > > > But, I am wondering if this is a dead-end anyway, and if this > > maintenance is really important and/or could cause backfiring.

Any

> > thoughts? > > > > Mike > > > > > I agree with everyone else that it is worthless to check as nothing

ever

> comes out. May be a left over from the two stroke era where there > actually was carbon generated. > > Sounds like a lean condition. Check to make sure the deceleration > enriching circuit in the carb is functioning. Any thing that

increases

> the ease of gas flow in and out of the engine can cause a lean > condition. High flow air filters and high flow exhausts have to be > compensated for as do modifications to the still air box. You need

to

> check all of the connections in the intake tract to make sure that

none

> are leaking air. You also have to check the exhaust system to make

sure

> there are no leaks before the end of the muffler. Check the

connection

> between the engine and the exhaust header pipe as that has caused > problems for some in the past. Check the connection between the

head

> pipe and the muffler itself. That's all I can think of at the

moment but

> it gives you some things to check. > Alan Henderson A13 Iowa